Session 4 (Cells) - MCB 181 Study Session 4 (Cells)...

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MCB 181 Study Session 4 (Cells)
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Learning Goals for Study Session 4 (Cells) Understand the general role of cells in the function of the organism. Briefly describe why microscopes are needed to study cells. Distinguish between prokaryotic and eukaryotic cells. Describe the major structural features of eukaryotic cells including those that distinguish animal and plant cells. Describe the structure and general function of cell membranes.
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Everything you do occurs fundamentally at the cellular level! Cells are the simplest collection of matter that can live! All living organisms are composed of cells and cells come only from preexisting cells. Cells are biochemical factories producing goods (e.g. proteins) and services (e.g. physical movements) for growth, development and reproduction of living organisms. To do this, cells use genetic information to build specific proteins and other substances and they convert energy into forms needed to perform the work of living. In this study session we describe the types of cells and their components that makeup living organisms.
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Microscopes are required to study cells and their components! A micrometer (µm) is a unit of length in the metric system equal to 10 -6 or one millionth of a meter. Most plant and animal cells range in diameter between 10 and 100 µm and are below the resolution of the human eye which can only resolve things that are 200 µm or larger. Bacteria are typically less than 1-2 µm in length and require powerful microscopes to see. Smaller yet are viruses that range in diameter between 50 to 100 nanometers (nm). A nm is 10 -9 meters! Components of cells such as the nucleus, mitochondria and chloroplast range in size between 1 and 5 µm and macromolecules such as proteins have diameters of less than 10 nm.
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Your cells and those of an elephant are similar in size! As cells get larger the ratio of the surface area to their internal volume gets smaller. As the surface area decreases in relation to the internal volume it is more difficult to exchange nutrients and waste materials with the external environment at a rate necessary to sustain cell activities. Therefore, cells are small to maximize their surface area to volume ratio and function with optimum efficiency.
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Two general types of cells: 1. Organisms in the domains Bacteria and Archaea have prokaryotic (primitive nucleus) cells. 2.
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This note was uploaded on 04/17/2008 for the course MCB 181R taught by Professor Leonard during the Spring '08 term at University of Arizona- Tucson.

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Session 4 (Cells) - MCB 181 Study Session 4 (Cells)...

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